This invention relates to pressure tools used to insert friction, press-fit bearings of jewel material, metal or other materials into clock or watch or instrument plates. Other parts such as collets, hands for example, onto clocks, watches or instruments can be similarly fitted. Modern bearings of all materials are press-fit into tightly fitting holes in the plates of watches, clocks or instruments. Many bearings are made of synthetic jewel material. Their position relative to the height at which they must be fixed is directly related to the height of the axle of the wheel or lever contained in the bearing hole. Precision positioning is necessary so that the freedom of the pivotal movement of the turning part and axle is not restrained as it would be if the bearing height be insufficient. If the end-shakes are excessive, the axle will shift vertically and cause its attached member to fall out of engagement with its connecting neighbor.
Also, many bearings, being made of jewel material are delicate and brittle. Sudden or excessive pressure would cause fracture or shattering of these bearings.
Existing tools which insert these bearings are complicated and very expensive. Such tools insert these bearings by levered hand pressure governed only by a stop-lock adjustment. Thus, only one hand is left to guide or manipulate the plate into which the bearing is being inserted. This type of pressure does not allow for a delicacy of touch or feel, often the difference between a successful operation and a shattered bearing. Also, the large expense involved makes its use prohibitive to the average watch and clock or instrument maker. In view of the foregoing, the main object of this invention is to provide a bearing inserting device that is simple, safe and allows both hands to guide the plate and allow for close-up judgment of the pressure to be applied, it allows pressure to be applied by gradual thread-bearing pressure and the design of the tool is such that it allows it to be made at a reasonable price, available to any mechanic involved in such work.
A significant feature of this invention is that its pressure upon the object to be press-fit is by screw-feed. By this method, the operator controls the gradual pressure required and yet obtains the sense perception which ensures the insertion without fracture.
Also, the pushers can be threaded with a metric pitch of either one or two threads per millimeter. The threaded disc which governs the pressure and depth to which the part to be pressed-fit is subjected can have on its upper surface the divisions of a full millimeter, half millimeter, inches or any division of a linear unit measurement. This serves as an accurate reference when endshakes or heights to which a press-fit part is to alter or adjust.